textproduct: Quad Cities

KEY MESSAGES

- Dense fog will be found across parts of the area early this morning.

- A cold front will bring scattered showers and thunderstorms (30-50% coverage) to the area late this afternoon into the overnight hours. A few of these storms could be severe with the primary hazards being gusty winds and locally heavy downpours. - An active pattern keeps rain chances on the table through the middle of next week with plenty of dry hours in between, but muggy to oppressive humidity returns.

SHORT TERM /THROUGH SATURDAY NIGHT/

Issued at 116 AM CDT Fri Aug 7 2026

Another morning of dense fog ahead with storm chances returning this afternoon and evening. A shortwave trough and an accompanying surface boundary is forecasted to swing in from the northwest with isolated to scattered (30-50%) storm coverage due to the positive tilt of the troughs limiting low-level WAA and mid-level moisture advection. In addition, subsidence ahead of the weak cold front will lead to 50-100 J/kg of SBCIN, inhibiting widespread convective initiation. That being said, latest CAM guidance is hinting that convection further upstream in southern Minnesota could organize into an MCS, propagating southeastward towards our CWA during the late afternoon. Due to the factors listed above and only modest instability in the form of 1000-1750 J/kg of SBCAPE, maintenance of any convection is unlikely. The SPC does have a Marginal Risk (Level 1 out of 5) for severe wind gusts west of a line between Keokuk, IA and Dubuque, IA, but this threat is conditional on convection even developing.

Heading into tonight, the trough clears the area as a weak high pressure takes its place. Northwesterly flow and CAA behind the front should allow lows to drop into the 60s and skies to clear. Dry conditions are expected to persist through the day on Saturday with seasonable highs in the low-to-mid-80s.

Enjoy the dry, mild conditions while you can before they disappear once again Saturday night. A couple shortwaves, one over the Central Plains and another on the backside of the longwave trough near Hudson Bay, are forecasted to deepen a low pressure along the Front Range in Colorado and Wyoming and push a weak surface trough into the Great Lakes region. These two lobes of low pressure are likely to form a low-level deformation zone over Minnesota and Iowa, enhancing the low-level WAA and convergence over the region and bringing PoPs back up (50-70%). While it is difficult to determine the severity of convection due to this event being nocturnal and potentially elevated with a developing warm front, the SPC does highlight a Marginal Risk (Level 1 out of 5) for severe storms in the southwest quarter of our CWA where a developing LLJ could support some convective organization and damaging winds.

LONG TERM /SUNDAY THROUGH THURSDAY/

Issued at 116 AM CDT Fri Aug 7 2026

Sunday-Monday...As the two shortwaves quickly move to the southeast, the deformation zone remain in place Sunday, but PoPs should decrease to 30-50% with the lack of upper-level dynamical support. The low pressure over the Central Plains is also expected to stall out which will be an issue heading into Sunday night as another subtle shortwave zooms across Wyoming into South Dakota and Nebraska. A second LLJ is likely to develop, spawning another round of showers and storms Sunday night into Monday. This shortwave trough will also reinvigorate the deformation zone and pull it northward. The increased southwesterly flow, low-level WAA, and moisture advection could lead to excessive heat developing, especially in our south where clearing skies are more likely. Current LREF guidance has a 20-30% chance of heat indices exceeding 100 degrees south of Interstate 80 Monday afternoon. Regardless though, dew points are going to be in the 70s, possibly in the mid-to-upper 70s (40-60% chance per 06.12z LREF guidance), making it feel muggy to oppressive outside even with potential cloud cover.

Tuesday-Thursday...Multiple shortwaves passages will keep precipitation chances around through the middle of next week, but these repeated passages should slowly push the deformation zone further south as high pressure eventually settles back in over the region. There is general consensus among the ensembles that a return to north-to-northeasterly flow in the low-levels should erode away at the high dew points and temperatures, returning to the area to seasonable conditions by the end of next week.

AVIATION /18Z TAFS THROUGH 18Z SATURDAY/

Issued at 1240 PM CDT Fri Aug 7 2026

In the wake of fog this morning, periods of MVFR ceilings continue across the area at all TAF sites. A storm system is forecast to move across the area later this afternoon into this evening with low confidence in the exact timing and locations. Used 3 to 4 hour prob30 window at each TAF site to account for the timing of these storms. If storms do occur than MVFR ceilings are possible in storms with periods of IFR to LIFR visibilities in the strongest storms. Conditions are expected to improve to VFR behind the storm but fog is possible tonight with MVFR to IFR visibilities possible after 06 UTC with conditions improving by 14 UTC Saturday. Southerly winds today will shift to the northwest behind the front from west to east.

DVN WATCHES/WARNINGS/ADVISORIES

IA...None. IL...None. MO...None.